Linux Workshop

FOSS

• Free and Open Source Software
• Free Software Foundation(FSF) by Richard Stallman
• Anyone is freely licensed to use, copy, study, and change the software in any way, and the source code is openly shared so that people are encouraged to voluntarily improve the design of the software

Benefits

• Decrease Software Cost
• Increase Security
• Stability
• Protect Privacy
• Give Users control over hardware

Licenses

• Copyleft - practice of offering people the right to freely distribute copies and modified versions of a work with the stipulation that the same rights be preserved in derivative works down the line. eg. GNU GPL3
• Licenses considered to have minimum restrictions of that kind, like Apache license, the BSD license, and the MIT license, are called permissive software licenses.

Examples

• Linux, Ubuntu, MySQL, Apache, Firefox, Libre
• Open Source Games - SuperTuxCart,Battle of Wesnoth,Minetest :P

Linux

• Unix like operating system mostly POSIX compliant
• The defining component of Linux is the Linux kernel, an operating system kernel first released on 5 October 1991 by Linus Torvalds - GNU License
• The underlying source code may be used, modified and distributed—​​commercially or non-commercially—​​by anyone under the terms of its respective licenses, such as the GNU General Public License. Typically, Linux is packaged in a form known as a Linux distribution, for both desktop and server use

• distributions include the Linux kernel, supporting utilities and libraries, and usually a large amount of application software to fulfill the distribution's intended use
• Debian, Ubuntu, Linux Mint, Fedora, openSUSE, Arch Linux and Gentoo, together with commercial Red Hat Enterprise Linux and SUSE Linux Enterprise Server distributions

Know the system

• uname
  The “uname” command stands for (Unix Name), print detailed information about the machine name, Operating System and Kernel.
  

$ uname -a
Linux arjun-SVF15218SNB 3.13.0-32-generic #57-Ubuntu SMP 
Tue Jul 15 03:51:08 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

					

• ls
  The command “ls” stands for (List Directory Contents), List the contents of the folder, be it file or folder, from which it runs.
  

$ ls

Android-Games                     Music
Pictures                          Public
Desktop                           Tecmint.com
Documents                         TecMint-Sync
Downloads                         Templates
					

• ls -l
  The command “ls -l” list the content of folder, in long listing fashion.
  

$ ls -l

total 162
-rwxrwxrwx 1 root root   523 Feb 24 10:52 bower.json
-rwxrwxrwx 1 root root  1062 Feb 24 10:52 CONTRIBUTING.md
drwxrwxrwx 1 root root     0 Feb 24 10:52 css
-rwxrwxrwx 1 root root  3338 Feb 24 10:52 Gruntfile.js
-rwxrwxrwx 1 root root  9413 Feb 25 11:32 index.html
drwxrwxrwx 1 root root     0 Feb 24 19:32 js
drwxrwxrwx 1 root root     0 Feb 24 10:52 lib
-rwxrwxrwx 1 root root  1075 Feb 24 10:52 LICENSE
-rwxrwxrwx 1 root root 21146 Feb 24 23:08 linusTorvalds.jpg
drwxrwxrwx 1 root root  4096 Feb 24 11:02 node_modules
-rwxrwxrwx 1 root root  1111 Feb 24 10:52 package.json
drwxrwxrwx 1 root root  4096 Feb 24 10:52 plugin
-rwxrwxrwx 1 root root 41365 Feb 24 10:52 README.md
-rwxrwxrwx 1 root root   364 Feb 24 19:08 session contents
drwxrwxrwx 1 root root     0 Feb 24 19:33 temp
drwxrwxrwx 1 root root  4096 Feb 24 10:52 test
-rwxrwxrwx 1 root root 50809 Feb 24 22:38 TuxWallpaper.jpg

					

• ls -a
  Command “ls -a“, list the content of folder, including hidden files(starting with ‘.’).
  

$ ls -l -a

drwxrwxrwx 1 root root  4096 Feb 24 23:08 .
drwxrwxrwx 1 root root     0 Feb 24 18:45 ..
-rwxrwxrwx 1 root root   523 Feb 24 10:52 bower.json
-rwxrwxrwx 1 root root  1062 Feb 24 10:52 CONTRIBUTING.md
drwxrwxrwx 1 root root     0 Feb 24 10:52 css
drwxrwxrwx 1 root root  4096 Feb 25 11:02 .git
-rwxrwxrwx 1 root root   123 Feb 24 10:52 .gitignore
-rwxrwxrwx 1 root root  3338 Feb 24 10:52 Gruntfile.js
-rwxrwxrwx 1 root root 10965 Feb 25 11:35 index.html
drwxrwxrwx 1 root root     0 Feb 24 19:32 js
drwxrwxrwx 1 root root     0 Feb 24 10:52 lib
-rwxrwxrwx 1 root root  1075 Feb 24 10:52 LICENSE
-rwxrwxrwx 1 root root 21146 Feb 24 23:08 linusTorvalds.jpg
drwxrwxrwx 1 root root  4096 Feb 24 11:02 node_modules
-rwxrwxrwx 1 root root  1111 Feb 24 10:52 package.json
drwxrwxrwx 1 root root  4096 Feb 24 10:52 plugin
-rwxrwxrwx 1 root root 41365 Feb 24 10:52 README.md
-rwxrwxrwx 1 root root   364 Feb 24 19:08 session contents
drwxrwxrwx 1 root root     0 Feb 24 19:33 temp
drwxrwxrwx 1 root root  4096 Feb 24 10:52 test
-rwxrwxrwx 1 root root    80 Feb 24 10:52 .travis.yml
-rwxrwxrwx 1 root root 50809 Feb 24 22:38 TuxWallpaper.jpg
					

Know your way around

• pwd
  pwd command (print working directory) prints the full pathname of the current working directory
  

$ pwd

/media/arjun/nv1/linux_workshop/reveal/css

					

• cd
  “cd” command stands for (change directory), it change the working directory to execute, copy, move write, read, etc. from terminal itself.
  

$ pwd
/media/arjun/nv1/linux_workshop/reveal

$ cd css

$ pwd
/media/arjun/nv1/linux_workshop/reveal/css
					

• cd ..
  changes working directory to the parent direcory
  

$ pwd
/media/arjun/nv1/linux_workshop/reveal/css

$ cd ..

$ pwd
/media/arjun/nv1/linux_workshop/reveal
					

• cd ~
  changes working directory to the home direcory
  

$ pwd
/media/arjun/nv1/linux_workshop/reveal/css

$ cd ~

$ pwd
/home/arjun/
					

• cd <Path to the directory>
  changes working directory to the directory given in the path
  

$ pwd
/home/arjun/

$ cd /media/arjun/nv1/linux_workshop/reveal

$ pwd
/media/arjun/nv1/linux_workshop/reveal

					

• history
  prints the history of the latest issued commands
  

$ history

 2001  ls -l
 2002  ls -a
 2003  ls -a -l
 2004  ls -l -a
 2005  ls -a
 2006  ls -a -l
 2007  pwd
 2008  ls
 2009  cd css
 2010  ls
 2011  pwd
 2012  cd .
 2013  cd ~
 2014  pwd
 2015  cd /media/arjun/nv1/linux_workshop/
 2016  ls
 2017  cd /media/arjun/nv1/linux_workshop
 2018  ls
 2019  cd /media/arjun/nv1/linux_workshop/reveal
 2020  ls
 2021  pwd
 2022  man history
 2023  history

					

Viewing and manipulating

• cat <filename>
  view the contents of the file in standard output
  

$ cat text.txt

Hi I am A text file

					

• more <filename>
  Allows file contents or piped output to be sent to the screen one page at a time.
  

$ more largetext.txt

Linux is, in simplest terms, an operating system. It is the software on a 
computer that enables applications and the computer operator to acces
s the devices on the computer to perform desired functions. 
The operating system (OS) relays instructions from an application to, for instance,
 the computer's processor. The processor performs the instructed task, then sends 
 the results back to the application via the operating system.
 --More--(82%)
					

• less <filename>
  Similar to the more command, but the user can page up and down through the file.
  

$ less text.txt



					

• mkdir <directory_name>
  Make a directory in the current working directory
  

$ ls -l

total 5
-rwxrwxrwx 1 root root 3163 Feb 25 12:52 largetext.txt
drwxrwxrwx 1 root root    0 Feb 25 12:51 temp
-rwxrwxrwx 1 root root   20 Feb 25 12:52 text.txt

$ mkdir mydirectory

$ls -l 

total 5
-rwxrwxrwx 1 root root 3163 Feb 25 12:52 largetext.txt
drwxrwxrwx 1 root root    0 Feb 25 12:53 mydirectory
drwxrwxrwx 1 root root    0 Feb 25 12:51 temp
-rwxrwxrwx 1 root root   20 Feb 25 12:52 text.txt


					

• cp <source> <destination>
  Copy file in the source to the destination path
  

$ cp text.txt mydirectory/mytext.txt



					

• -r modifier is used to recursively copy files(used for directories)

• mv <source> <destination>
  Move file from the source to the destination path
  

$ mv text.txt mydirectory/movedtext.txt



					

Rename ??

mv <initial_name> <final_name>
rename the target from initname to finalname


$ mv text.txt myrenamedtext.txt



					

Redirection of Input and Output

• Input and output are distributed accross three streams
• Standard Input (stdin 0)
• Standard Input (stdout 1)
• Standard Input (stderr 2)

Standard Output

• Writes the data that is generated by a program
• Generally it outputs to the terminal

• echo "Hello World"

• However we can redirect to anywhere - files, devices, or other commands - using

   > 

  or

   >> 

• echo "Hello World" > hello_world.txt

  less hello_world.txt

  echo "Linux is fun" >> hello_world.txt

  less hello_world.txt

Standard Input

• Reads data from the user usually from keyboard
• Terminated by reaching End of file (EOF)

• cat

• EOF can be input by using Ctrl-d
• Redirection using

   < 

  or

   << 

• cat hello_world.txt

All redirection commands

Overwrite

 
 > - standard output
								
 < - standard input
								
 2> - standard error

Append

 >> - standard output 
								
 << - standard input 
								
 2>> - standard error

Pipes and Filters

Pipes

• Pipes redirect streams from one program to another.
• The standard output of the first command is sent to the input of second command

ls | less

• It will print the files and directories line by line

Filters

• Filters are commands that alter piped redirection and output
• Filter commands are also standard Linux commands that can be used without pipes

 
							
find - Returns files with filenames that match the argument passed to find
							
grep - Grep returns text that matches the string pattern passed to grep
							
tr - finds-and-replaces one string with another.
							
wc - counts characters, lines, and words.
						

Wildcards

• A wildcard is a character that can be used as a substitute for any of a class of characters in a search
• It increases the flexibility and efficiency of searches
• Star wildcard
• Question Mark Wildcard
• Square Bracket wildcard

Star Wildcard

• Represented by *
• It matches to anything and everything
• Represents any string of zero or more characters
• List all html files

  ls *.html

• Remove all files of Project X

  rm *projectX*

Question Mark Wildcard

• Represented by ?
• Used to represent exactly one character
• If used in succession, represent multiple characters
• List all files with three letter names

  ls ???

• Can u list all files with three letter extensions

Square Brackets

• It can represent any one of the characters in the brackets
• Listing all files starting with x or y

  ls [xy]* 

• Hyphen is used to represent a range
• Listing all files starting with any character from a to g

  ls [a-g]* 

• Ranges and individual characters can be combined
• Listing all files starting with any character from a to g or from x or y

  ls [a-gxy]*

• List all files that contain a three digit number

  ls *[0-9][0-9][0-9]*

Permissions

Each file has three premission groups

• owner- owner permissions apply to only the owner of the file
• group - It applies to the only group that has been assignedto the file
• all - It applies to everyone else

There are three types of permissions

• Read - User permission to read
• Write - User premission to write
• Execute - User premission to execute

View permissions - ls -l

Changing Permission - chmod

• Each of the permission type is represented as r for read, w for write and x for execute
• Each group can be represented as u for owner, g for group, a or o for all
• To remove execute and write permissions for all users

  chmod a-wx file

• To give read and execute permissions for group

  chmod g+rx file

• To give all permissions to owner

  chmod u+rwx file

• Use + to grant and - to remove permissions

Binary Refernces

• Each of the permission type for each of the group can be 0 or 1
• Total possible for each group are 8
• Permissions can be represented as a number between 0 to 7
• Example

  chmod 640

• This would change permission to 6 for owner, 4 for group and 0 for everyone
• 6 in binary is 110 i.e. read and write permissions are set
• 4 in binary is 100 i.e. read only permissions

Change user and group

• Change the owner and group via chown command

chown owner:group file

• Example:

  chown skidm09:wireshark index.html

• d in the first bit indicates directory. l indicates symbolic link
• Set permissions with caution. Remember to set only the neccessary permissions for any directory

Installing and removing packages in Ubuntu

• APT is the application package tool of Ubuntu
• apt-get is a command line tool that works with APT
• Installing package

  sudo apt-get install apache2

• Remove a package

  sudo apt-get remove apache2

• Update the package index

  sudo apt-get update

• Upgrade

  sudo apt-get upgrade

• Get help

  apt-get help